At the moment, I use Octane 87 with Tactrol from Perto Canada in my P5 regularly. Will using Octane 89 gas hurt the FS-DE? Sure it's more expensive, but won't I get a little smoother of an idle, etc. with the higher Octane rating? Has anyone else out there run a different grade than 87 on their FS-DE? What would you reccomend?

 

i use 89 in my 1st gen, just because i'm too good for the cheap stuff, but too cheap for the good stuff... although i do use 92 on occasion.

it has been known to smooth out and improve mpg...more a cse by case basis though as this can get into a heated subject discussion....

My advice, is try it, see how your car repsonds and record your mileage. Try it with more than just one tank full...maybe an average between 3 tank fulls of each grade.

 

I did a search earlier on this topic, but this one didn't come up. I see you used "Octane" as the keyword. I can't remember what I used, but thanks anyway for the link! Helped alot!

 

my car runs alot smother with the 89 octain gas